JPH05223204A - Generating method for vapor utilizing heat pump - Google Patents

Abstract

PURPOSE:To eliminate a fear of corrosion, an explosion, a fire due to combustion, to enhance an energy efficiency and to improve economy by continuously generating vapor under a predetermined pressure by a heat pump without using combustion. CONSTITUTION:A passage for fluid to be heated is annexed to a condenser 2 of a refrigerating cycle having a compressor 1, the condenser 2, a refrigerant throttle tube 3 and an evaporator 4, and the condenser is used to output vapor in a heat pump. As the refrigerant, refrigerant having a critical temperature of 100 deg.C or higher is used. The cycle is so maintained that at least 87% of enthalpy of the refrigerant for supplying heat to the condenser becomes a temperature of 100 deg.C or higher, thereby operating the pump.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing steam using a heat pump, and more particularly to the above method for producing steam by a refrigeration cycle using a refrigerant having a critical temperature of 100 ° C. or higher as a refrigerant. ..

[0002]

2. Description of the Related Art Conventionally, heat pumps have been used for air conditioning (heating) and hot water supply by using the heat output on the high temperature side (high pressure side). High pressure equivalent saturation temperature) is as low as around 40 ℃, and is about 60 ℃ at maximum, so it is used as hot water at 40-60 ℃ for air conditioning and hot water supply. Of course, it is also possible to heat water above the condensation temperature (saturation temperature) of the refrigerant, and for water above the saturation temperature, the refrigerant entering the condenser is overheated, for example, at 120 ° C, so the heat source temperature is The water temperature above the saturation temperature can be obtained by utilizing this. However, of the total amount of heat until the refrigerant enters the condenser, is cooled, and is liquefied at the outlet, only the superheated region of the refrigerant can contribute to the rise in the water temperature. For example, the energy (enthalpy) to turn water into steam is approximately 620 kcal / kg, and the breakdown is 80 kcal / kg for water up to 20 ℃ → 100 ℃, and water for 100 ℃ → 10
The amount of heat is 540 kcal / kg with 0 ° C saturated steam. In other words, 87% of heat energy is required as a heat source of 100 ℃ or higher for water vaporization.

However, at present, low boiling point refrigerants such as R-22 and R-12 which are generally used for household use have a critical temperature of 90 to 100 ° C., so that they are used as a heat source above the condensation temperature given to water. Energy around% (enthalpy)
It is usually possible to make a contribution only, and hot water is made with the remaining low-temperature energy or is discarded as waste heat. Therefore, steam is mostly produced by a boiler using combustion (oil, gas heat source) with high heat source temperature.

[0004]

SUMMARY OF THE INVENTION The present invention addresses the above situation and attempts to positively utilize the heat radiated in the condenser of the refrigeration cycle, particularly at 100 ° C. for producing steam at 100 ° C.
By finding stable maintenance of the high temperature side (high pressure side) of the refrigeration cycle so that the saturation temperature itself becomes 100 ° C or higher as the above heat source, it is possible to continuously generate steam at a constant pressure without using combustion. The purpose is to eliminate the risk of corrosion, explosion, and fire due to heat, improve energy efficiency, and improve economic efficiency.

[0005]

That is, the feature of the vapor generating method of the present invention which meets the above object is that the fluid to be heated flows through the condenser of the refrigeration cycle including the compressor, the condenser, the refrigerant throttle pipe and the evaporator. In a heat pump with a passage for the condenser for vapor extraction, a refrigerant with a critical temperature of 100 ° C or higher is used as the refrigerant, and at least 87% of the enthalpy of the refrigerant that heats the condenser is 100 ° C. The refrigeration cycle is maintained so that the temperature becomes the above temperature, and the heat pump is operated. More specifically, in the present invention, first, it is necessary to use a refrigerant having a saturation temperature of 100 ° C. or higher, that is, a critical temperature (a temperature at which gas is not liquefied) of 100 ° C. or higher. Such a refrigerant needs to be stable at the design temperature without decomposing and deteriorating. For example, R-123, R
There are -11 etc. These usually have a critical temperature of 120-18.
It is about 0 ° C. Therefore, refrigerating machine oil that lubricates the compressor is also selected for high temperatures and is suitable as a refrigerant. Further, it is preferable to control the amount of water supplied to the heating condenser so that the amount of water supplied matches the heating capacity. If water having a heating capacity or more is supplied, the steam pressure will decrease, and if it is too large, it will end up as warm water. The condenser that radiates heat from the high temperature heat source is designed according to the heat radiation temperature and the temperature equivalent to the compressor discharge pressure. On the other hand, the evaporator that absorbs heat from the low temperature heat source is designed according to the heat absorption temperature and the temperature equivalent to the suction pressure of the compressor. Also, maintaining the refrigeration cycle so that at least 87% of the enthalpy of the refrigerant that supplies heat to the condenser is at a temperature of 100 ° C or higher means that the energy for converting water into steam is approximately 620 kcal / 80 kg / kg of water up to 20 ℃ → 100 ℃, 100 ℃ of water →
87% with a calorific value of 540 kcal / kg with 100 ° C saturated steam
This is because the heat source temperature that gives the heat energy of is necessary for the vaporization of water at 100 ° C. If it is less than 87%, water is not vaporized and the object of the present invention is difficult to achieve.

[0006]

According to the above-mentioned method of the present invention, heat is drawn from the fluctuating low temperature side heat source, an appropriate amount of water is supplied to the refrigerant condenser, combustion is not used, and steam is continuously and automatically obtained at a constant pressure. be able to.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of an apparatus for carrying out the method of the present invention. In the figure, a compressor (1), a condenser (2),
Refrigerant throttle pipe (capillary tube) (3), evaporator (4), and further accumulator (5) are sequentially connected to form a refrigeration cycle, and the outlet side of evaporator (4) and compressor (1) ) A low pressure switch (9) and a high pressure switch (10) are provided on the discharge side, respectively.

A fluid to be heated, such as water, is supplied to the condenser (2) from a hot water storage tank (14) such as a bath through a water supply pump (11) and a water throttle pipe (capillary tube) (12). Water is supplied into a heated fluid flow passage provided alongside, and water is heat-exchanged with the refrigerant in the opposite flow in the passage to form steam as a vapor pressure regulator (6), a gas-liquid separator (7),
It is taken out from the steam outlet through the stop valve (8),
When there is hot water mixed with steam, the hot water is separated by the gas-liquid separator (7) and is returned to the hot water storage tank.

On the other hand, the hot water storage tank (1
4) a circulation system (13) is passed through the circulation pump (13) to reach the inside of the penetrating path provided in the evaporator (4), and a piping system is provided for countercurrently exchanging heat with the refrigerant and returning it to the hot water storage tank (14) again. At the same time, the pipe with valve leading to the hot water supply port is connected. Incidentally, (17) is a makeup water tank, which is appropriately supplied with water and takes charge of water supply to the hot water storage tank (14), while the hot water storage tank (1
The pipe leading to the hot water inlet pipe is branched and connected from the middle of the pipe to 4) directly through the circulation pump (15) and the water heater (16). In addition, the hot water storage tank (14) has a drain valve (2) through an upper safety valve (19) for overflow.
0) and the drain (2) via the stop valve (18).
The pipes leading to 0) are connected to each other.

In the above apparatus, however, the amount of water supplied to the condenser (2) is controlled to match the heating capacity, and the condenser (2) that radiates heat from the high temperature heat source corresponds to the heat radiation temperature and the compressor discharge pressure. The design according to the temperature and the design of the evaporator (4) that absorbs heat from the low-temperature heat source according to the endothermic temperature and the temperature equivalent to the suction pressure of the compressor are as described above. Further, the amount of steam generated in the condenser (2) varies depending on the amount of heat absorbed by the evaporator (4), and when the amount of generated steam becomes excessive, the steam pressure rises, causing a high temperature danger and a heat source for cooling the refrigerant. Since the temperature rises, the condensing pressure (temperature) rises and the desired vapor temperature cannot be obtained. Therefore, in order to obtain steam with a constant pressure or a constant temperature, a steam pressure regulator (6) for adjusting the amount of steam discharged at the outlet of the condenser (2) is attached. Stop the device or close the stop valve (8) at the steam outlet, but if the stop valve (8) is closed, the pressure will rise, so even if there is an outlet pressure control valve, it will be an abnormally high pressure (high temperature). The device is stopped by receiving a signal from the switch (10) or a temperature sensor attached to the outlet.

On the other hand, the low temperature side heat source temperature is lowered, the refrigerant evaporation temperature in the evaporator (4) is lowered, the compressor suction pressure is lowered, and the compression ratio is increased, which is not preferable. Therefore, a low pressure switch (9) is provided to protect the compressor even when the pressure is abnormally low.
The device is being stopped.

Next, an embodiment in which steam is specifically generated using the above apparatus will be described in accordance with the following specifications, taking a small once-through type low-pressure steam generating heat pump as an example. (1) Freon R-123 is specified as the refrigerant (2) Compressor uses a closed type (rotary compressor with liquid injection) (3) Evaporator and condenser use a double pipe system (4) Condenser Liquid refrigerant expansion (flow restriction) from the evaporator to the evaporator was performed by the capillary tube. (5) The feed water flow rate adjustment to the condenser was performed by the capillary tube and the variable discharge pressure type pump. (6) As a heat source on the low temperature side. (7) Operated at steam pressure of 0.5 kg / cm2G (equivalent temperature is 110 ° C). The specific operating conditions according to the above specifications were as follows. The operating state of the refrigeration cycle and Table 2 show the operating state of each device. In Table 1, the values in parentheses are reference approximate values that are not actually measured values. Margin below

[0014]

[Table 1]

[0015]

[Table 2]

2 (a) and 2 (b) are a Mollier diagram and a temperature gradient diagram showing the operating state of the heat pump of the present invention using the refrigerant CFC R-123 in Tables 1 and 2 above. At the position (A) of operating point 2 entering the condenser inlet, the refrigerant has a temperature of 127.6 ° C. as shown in FIG. On the other hand, as shown in Fig. (B), water (warm water) at 54.5 ° C enters the condenser, and vaporization starts when the temperature rises to 110.4 ° C. Above, the required enthalpy is 56 Kcal from the physical properties of water
/ kg. Then, the above vaporization starts, and 110.4
An additional 532 Kcal / kg enthalpy is required to reach saturated steam at ℃. Therefore, a total of 56 + 532 = 588 Kcal / kg enthalpy is required to convert 54.5 ° C water to 110.4 ° C saturated steam. Generally, in order to convert 20 ° C water to 100 ° C steam, 80Kcal / kg, 100 ° C at 20 ° C → 100 ° C water as described above.
Of water → saturated steam at 100 ℃ requires 540 Kcal / kg heat quantity, the ratio of the latter heat quantity to the total heat quantity 620 Kcal / kg is 540/620 = 8
7.1%, and at least 87% requires a refrigerant temperature of 100 ° C or higher. In the above experimental example of the present invention, 532/588 = 90.5%
Is more than 87%. And operating points 2 in Table 1
The refrigerant temperature of No. 3, that is, the refrigerant side temperature between A and B in FIG. 2B is 127.6 to 104.1 ° C., which is 100%, 100 ° C. or higher. Although the enthalpy of Table 1 is shown in FIG. 2 (a), it is 159.7 Kcal / kg-12 between A and B.
4.8Kcal / kg = 34.9Kcal / kg. Assuming this to be 100%, 9.5% and 90.5% in the above-mentioned experimental example are 3.3 Kca.
l / kg, 31.6Kcal / kg, 3.3Kca at 54.5 ℃ → 110.5 ℃
l / kg is consumed, and 31.6 Kcal / kg is consumed in the vaporization at 110.5 ℃. Thus, it is understood that the method of the present invention is extremely effective for steam generation using a heat pump.

[0017]

As described above, the present invention uses a refrigerant having a critical temperature of 100 ° C. or higher as a refrigerant, and at least 87% or more of the enthalpy of the refrigerant to be supplied to the condenser on the high temperature side of the refrigeration cycle is 100% or more. It is a method of operating so that the refrigeration cycle is maintained so that the temperature becomes ℃ or more, and it is possible to generate steam by the heat of condensation on the high temperature side of the heat pump, which could hardly be generated in the past. It is possible to achieve steam generation with good controllability without using. Further, as mentioned above, since combustion is not used, corrosion does not occur in the method of the present invention, the life of the equipment can be extended, and safety can be improved without fear of explosion or fire. Furthermore, since it is a compression heat pump, it has the advantages that it does not pollute the atmospheric environment, it is energy efficient, and it is economical in terms of operating costs.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an apparatus for carrying out the method of the present invention.

FIG. 2 is a diagram showing an operating state of a heat pump operation according to the present invention, (a) is a Mollier diagram, and (b) is a temperature gradient diagram.

[Explanation of symbols]

 (1) Compressor (2) Condenser (3) Refrigerant throttle pipe (4) Evaporator (11) Water supply pump (12) Water throttle pipe (13) Circulation pump (14) Hot water tank (15) Circulation pump (16) Water heater (17) Make-up water tank

Claims (1)

[Claims] 1. A heat pump, wherein a condenser for a refrigerating cycle including a compressor, a condenser, a refrigerant throttle valve, and an evaporator is provided with a heated fluid flow path, and the condenser is used for taking out vapor. Use a refrigerant with a critical temperature of 100 ° C or higher as the refrigerant for the refrigeration cycle, and maintain and operate the refrigeration cycle so that at least 87% of the enthalpy of the refrigerant that heats the condenser is 100 ° C or higher. Characteristic steam generation method using a heat pump.